Microsoft may have just launched Windows Phone 8-based products, but the company also plans to offer older Windows Phone 7 and 7.5 devices a new software upgrade to Windows Phone 7.8. The new version reportedly has reached the RTM stage.

Some owners of those older phones, particularly the Nokia Lumia 900, which was released in April, have express disappointment they would not be receiving the full Windows Phone 8 upgrade. However, in a new interview with TechRadar, Microsoft's Windows Phone corporate vice president Terry Myerson said we will learn more about Windows Phone 7.8 in the coming weeks.

Myerson added that Microsoft appreciates all of the people who have bought Windows Phone products since the company launched its revamped mobile OS in the fall of 2010. He said:

I would expect both platforms to exist for quite some time, from a global point of view. Windows Phone 7.8 devices will span much lower price points than Windows Phone 8 devices, initially, and given the application compatibility across the platforms, it makes the ecosystem stronger to have more device and more price points. We value every 7 and 7.8 customer we have; we'll continue to work for them as well but it is true that Windows Phone 8 is our future platform.

Myerson also added that while Samsung and HTC get their share of support from Microsoft, it is Nokia who gets some special treatment in terms of their own Windows Phone devices. He said, "Nokia is exclusive to Windows Phone and we definitely, on the engineering side, prioritise platform work to support their differentiation coming through."